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authorIngo Molnar <mingo@kernel.org>2016-09-20 16:58:59 +0200
committerIngo Molnar <mingo@kernel.org>2016-09-20 16:58:59 +0200
commit41a66072c32978ff3914fd6be88f7592ef64bef7 (patch)
tree0f38ef433f0feea3e58f61f8d5397cd9bf065559 /include/linux/compiler.h
parent5465fe0fc3316f7cdda66732a7986f4ebe76d949 (diff)
parent7597cdc066313bfd211cca2f9252dfeb41271391 (diff)
Merge branch 'efi/urgent' into efi/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/compiler.h')
-rw-r--r--include/linux/compiler.h7
1 files changed, 4 insertions, 3 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 436aa4e42221..668569844d37 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -527,13 +527,14 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
* object's lifetime is managed by something other than RCU. That
* "something other" might be reference counting or simple immortality.
*
- * The seemingly unused size_t variable is to validate @p is indeed a pointer
- * type by making sure it can be dereferenced.
+ * The seemingly unused variable ___typecheck_p validates that @p is
+ * indeed a pointer type by using a pointer to typeof(*p) as the type.
+ * Taking a pointer to typeof(*p) again is needed in case p is void *.
*/
#define lockless_dereference(p) \
({ \
typeof(p) _________p1 = READ_ONCE(p); \
- size_t __maybe_unused __size_of_ptr = sizeof(*(p)); \
+ typeof(*(p)) *___typecheck_p __maybe_unused; \
smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
(_________p1); \
})